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Jean Delvareba224e22006-12-12 18:18:29 +01001Kernel driver pc87427
2=====================
3
4Supported chips:
5 * National Semiconductor PC87427
6 Prefix: 'pc87427'
7 Addresses scanned: none, address read from Super I/O config space
8 Datasheet: http://www.winbond.com.tw/E-WINBONDHTM/partner/apc_007.html
9
10Author: Jean Delvare <khali@linux-fr.org>
11
12Thanks to Amir Habibi at Candelis for setting up a test system, and to
13Michael Kress for testing several iterations of this driver.
14
15
16Description
17-----------
18
19The National Semiconductor Super I/O chip includes complete hardware
20monitoring capabilities. It can monitor up to 18 voltages, 8 fans and
216 temperature sensors. Only the fans are supported at the moment.
22
23This chip also has fan controlling features, which are not yet supported
24by this driver either.
25
26The driver assumes that no more than one chip is present, which seems
27reasonable.
28
29
30Fan Monitoring
31--------------
32
33Fan rotation speeds are reported as 14-bit values from a gated clock
34signal. Speeds down to 83 RPM can be measured.
35
36An alarm is triggered if the rotation speed drops below a programmable
37limit. Another alarm is triggered if the speed is too low to to be measured
38(including stalled or missing fan).